Liverpool manager Jurgen Klopp will be up against a familiar face as his side take on Huddersfield Town in a preseason friendly on Wednesday night.
The Reds travel to West Yorkshire for their fourth warm-up game of the summer and face the tough test of David Wagner's Championship outfit.
Wagner and Klopp are long-time friends, having played together at Mainz before the pair worked together at Borussia Dortmund.
"David Wagner is one of my best friends, maybe my best friend," Klopp said on the club's official website. "We played a few years together and we didn't only play, we celebrated a few times!
"He was my coach of our under-23 side in Germany with Borussia Dortmund. He is an experienced manager. He has worked in youth teams and he has done a really good job up until now.
"He made a big impact, I heard, when he went to Huddersfield. It changed a lot and that's really good."
The meeting excites Klopp, with it coming just hours before the team fly out to the United States for their preseason tour.
He added: "Playing against a Championship team in a preseason game is really difficult because they are really hot.
"They are greedy, they are ambitious and sometimes, maybe sometimes, it's one of the best games in their whole year -- so no big pressure and only opportunity.
"It will be difficult, 100 percent. We have a long day on Wednesday because we fly to the USA after the game for our tour. It's not easy for us but at the end of the day I want difficult situations in the preseason.
"I know a few players [in the Huddersfield team] because they have brought in a few German players and I managed two of them in the past. They are a really good team, for sure, and it's a good challenge for us."
Klopp, who took over the Anfield hotseat in October, was quickly followed into English football by Wagner after he was appointed Terriers boss in November.
Despite the closeness between the pair, they were both unaware of the other's next appointment, which made for an interesting conversation when they next met up.
"In this business, with your best friends you have to keep a few secrets," Klopp said. "He didn't know I went to the USA to speak with our owners and I actually had no idea that he was in talks with another English club.
"When I came back from the USA, I opened the door and first of all I saw his car sitting in front of my house and I thought 'What's he doing here?' When I came in my wife said 'Let him tell first!'
"I said 'You first.' He said he had spoken to a Championship club in England. I said 'Interesting, which club?' He said Huddersfield and I thought 'OK, close to Liverpool.'
"I said I had come back from talks with Liverpool! So that's how it was and a completely strange situation for both of us.
"We are pretty close to each other and it's good. He's a really good friend but more importantly for Huddersfield he is a brilliant manager. So a win-win situation!"